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BRL Abstracts Database |
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Your search for ultrasound produced 3296 results. Page 43 out of 330
| Title |
Applications of neural networks to ultrasound tomography. |
| Author |
Conrath BC. |
| Journal |
Thesis(MS): Univ of Illinois |
| Volume |
|
| Year |
1990 |
| Abstract |
No abstract available. |
| Title |
Applications of neural networks to ultrasound tomography. |
| Author |
Conrath BC, Daft CMW, O'Brien WD Jr. |
| Journal |
Proc Ultrason Symp IEEE |
| Volume |
|
| Year |
1989 |
| Abstract |
Ultrasound tomography holds promise in the area of medical diagnosis but is limited by the inadequacies of current reconstruction algorithms. An alternative method using neural networks is presented. The theory begins with X-ray tomography and is extended to ultrasound. After theoretical relevance is introduced, several experiments are discussed to illustrate the effectiveness of neural networks. The model was a circular cylinder with acoustic properties of tissue, insonated by a line source at 2 MHz. The transducers were arranged in a ring surrounding the cylinder, with one being the transmitter. The experiments involved varying the acoustic speed and the radius of the cylinder. In both cases, the neural network was able to generalize to parameters other than the ones used during the training. |
| Title |
Applications of neural networks to ultrasound tomography. |
| Author |
Conrath BC, Daft MW, O'Brien WD, Jr. |
| Journal |
Proc IEEE Ultrasonic Symposium |
| Volume |
|
| Year |
1989 |
| Abstract |
Ultrasound tomography holds promise in the area of medical diagnosis but is limited by the inadequacies of current reconstruction algorithms. An alternative method using neural networks is presented. The theory begins with X-ray tomography and is extended to ultrasound. After theoretical relevance is introduced, several experiments are discussed to illustrate the effectiveness of neural networks. The model was a circular cylinder with acoustic properties of tissue, insonated by a line source at 2 MHz. The transducers were arranged in a ring surrounding the cylinder, with one being the transmitter. The experiments involved varying the acoustic speed and the radius of the cylinder. In both cases, the neural network was able to generalize to parameters other than the ones used during the training. |
| Title |
Applications of ultrasound in dentistry. |
| Author |
Walmsley AD. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
1988 |
| Abstract |
An ultrasonic descaler working at kHz frequencies is used in dentistry to remove attached deposits from the teeth. Such devices offer many advantages over conventional hand instruments by reducing both the work and time involved in the clinical descaling process. Although it is a recognised clinical instrument, there has been little attempt to standardise its acoustic power output. A parameter which may characterise adequately the acoustic emission from these instruments is the displacement amplitude of the probe tip. Modification of the ultrasonic descaler generator has led to the further use of the instrument in other dental areas. Diagnostic applications of MHz ultrasound is limited by the structure and arrangement of the dental tissues. Therapeutic ultrasound has been used to treat a variety of dentally related ailments, and ultrasonic cleaning baths are used to clean both dental instruments and materials.
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| Title |
Applications of ultrasound to food systems. |
| Author |
Javanaud C. |
| Journal |
Ultrasonics |
| Volume |
|
| Year |
1988 |
| Abstract |
This review provides a comprehensive survey of the use of ultrasonic techniques with regard to foods. Experimental work on a wide range of foodstuffs is reviewed critically and summarized in tabular form. The difficulties inherent in using ultrasonics to provide useful information (e.g. structural or compositional) about foods are discussed in relation to those arising in biological media. Possible directions of future research are considered. |
| Title |
Applications of ultrasound to materials chemistry. |
| Author |
Suslick KS. |
| Journal |
MRS Bull |
| Volume |
|
| Year |
1995 |
| Abstract |
No abstract available. |
| Title |
Approach to 3-D ultrasound high resolution imaging for mechanically moving large-aperture transducer based upon fourier transform. |
| Author |
Benenson ZM, Elizarov AB, Yakovleva TV, O'Brien WD Jr. |
| Journal |
IEEE Trans UFFC |
| Volume |
|
| Year |
2002 |
| Abstract |
A new three-dimensional (3-D) acoustic image formation technique is proposed that is based on the transmission of wide bandwidth pulse signals and the application of the 3-D fast Fourier transform. A solution to the Helmholtz wave equation has been obtained using the Born approximation. The solution contains analytical expressions for the spatial spectra of the transmit and receive radiation patterns for transducers of various geometries with lenses of fixed focal distances. It has been shown that the proposed algorithms allow for radiation patterns with constant widths at depths both behind and in front of the focal point, starting practically from the plane of the transducer. The theoretical and experimental investigations and computer simulation for both spherical and rectangular transducer shapes have been performed. The results were used to estimate the beamwidths and the side lobe levels. A variant of the linear array has been studied for a cylindrical lens of a fixed focal distance moving in a lateral direction. It has been shown that, in this case, a high resolution (of the order of a few wavelengths) can be achieved along all three Cartesian coordinates at a very high scanning velocity. The influence of the moving scatterers' velocity in inhomogeneous medium on the spatial radiation pattern characteristics has been estimated. |
| Title |
Approaches to determining foetal hazard from ultrasound. |
| Author |
Donald I. |
| Journal |
Proc Br Inst Radiol |
| Volume |
|
| Year |
1971 |
| Abstract |
No astract available. |
| Title |
Arc back projection with an efficient computation for ultrasound reflection mode tomography. |
| Author |
Ikegami M, Yamamoto T, Aoki Y. |
| Journal |
Acoust Imaging |
| Volume |
|
| Year |
1987 |
| Abstract |
No Abstract Available. |
| Title |
ARFI imaging for noninvasive material characterization of atherosclerosis. Part II: toward in vivo characterization. |
| Author |
Behler RH, Nichols TC, Zhu H, Merricks EP, Gallippi CM. |
| Journal |
Ultrasound Med Biol |
| Volume |
|
| Year |
2009 |
| Abstract |
Seventy percent of cardiovascular disease (CVD) deaths are attributed to atherosclerosis. Despite their clinical significance, nonstenotic atherosclerotic plaques are not effectively detected by conventional atherosclerosis imaging methods. Moreover, conventional imaging methods are insufficient for describing plaque composition, which is relevant to cardiovascular risk assessment. Atherosclerosis imaging technologies capable of improving plaque detection and stratifying cardiovascular risk are needed. Acoustic radiation force impulse (ARFI) ultrasound, a novel imaging method for noninvasively differentiating the mechanical properties of tissue, is demonstrated for in vivo detection of nonstenotic plaques and plaque material assessment in this pilot investigation. In vivo ARFI imaging was performed on four iliac arteries: (1) of a normocholesterolemic pig with no atherosclerosis as a control, (2) of a familial hypercholesterolemic pig with diffuse atherosclerosis, (3) of a normocholesterolemic pig fed a high-fat diet with early atherosclerotic plaques and (4) of a familial hypercholesterolemic pig with diffuse atherosclerosis and a small, minimally occlusive plaque. ARFI results were compared with spatially matched immunohistochemistry, showing correlations between elastin and collagen content and ARFI-derived peak displacement and recovery time parameters. Faster recoveries from ARFI-induced peak displacements and smaller peak displacements were observed in areas of higher elastin and collagen content. Importantly, spatial correlations between tissue content and ARFI results were consistent and observable in large and highly evolved as well as small plaques. ARFI imaging successfully distinguished nonstenotic plaques, while conventional B-mode ultrasound did not. This work validates the potential relevance of ARFI imaging as a noninvasive imaging technology for in vivo detection and material assessment of atherosclerotic plaques. |
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